Digital networks have been developed to facilitate the transfer of information, including data and programs, among digital computer systems and other digital devices. A variety of types of networks have been developed and implemented, including so-called “wide-area networks” (WAN's) and “local area networks” (LAN's), which transfer information using diverse information transfer methodologies. Generally, LAN's are implemented over relatively small geographical areas, such as within an individual office facility or the like, for transferring information within a particular office, company or similar type of organization. On the other hand, WAN's are generally implemented over relatively large geographical areas, and may be used to transfer information between LAN's as well as between devices that are not connected to LAN's. WAN's also include public networks, such as the Internet, which can carry information for a number of companies.
Generally, in both LANs and WANs route information is transferred among devices connected in networks in the form of message packets, employing routers, bridges, gateways and other switching devices (generally, routers) to transfer the message packets thereamong. The routers are interconnected in a mesh pattern. A LAN that is connected to a WAN typically includes a firewall to mediate communications between the LAN and the WAN. Since the routers in a LAN, as well as a WAN, are connected in a mesh pattern, errors can arise in which message packets are transferred in loops. As more and more message packets are caught up in a loop, the network bandwidth devoted to such message packets increases, decreasing the bandwidth available for other message packets at least in that region of the network.
To address this problem, message packets are typically provided with “time to live” information, which allows a message packet to be discarded if it remains in the network for too long a time. Typically, both LANs and WANs make use of message packet transfer protocols conforming to, for example, the well-known Internet protocol (“IP”), which specifies a relatively long time to live. While this does not cause a significant problem in WANs such as the Internet, it can allow message packets caught in a loop in a LAN to live for a long enough period of time that they can seriously degrade network performance.